RadGrid cannot edit in IE8 under 2014Q2
javascript thows errors:
URI: http://localhost/Telerik.Web.UI.WebResource.axd?_TSM_HiddenField_=RadScriptManager1_TSM&compress=1&_TSM_CombinedScripts_=%3b%3bSystem.Web.Extensions%2c+Version%3d4.0.0.0%2c+Culture%3dneutral%2c+PublicKeyToken%3d31bf3856ad364e35%3azh-CN%3a8f393b2b-3315....

To fix the upper problem, we appyied 2014Q2SP1, however, in IE8, javascript thows new errors:
“sys is undefined” 
and the RadGrid does not display in web. But this is ok in debuging mode.

I am using the following grid:
   <telerik:RadGrid style="overflow: hidden" CssClass="dm-Grid" ID="gridView" runat="server" AllowPaging="false" PageSize="25" Skin="TylerSilver" EnableEmbeddedSkins="false" EnableViewState="true"
            ExportSettings-ExportOnlyData="true" ExportSettings-IgnorePaging="true" AutoGenerateColumns="false" SortingSettings-SortedBackColor="#F0F0F0" EnableAlternatingRowColor="true"
            EnableAjaxSkinRendering="true" AllowSorting="true" ShowGroupPanel="false" GroupPanel-Enabled="false"
            ClientIdMode="AutoId" AllowFilteringByColumn="true" onneeddatasource="gridView_NeedDataSource" Onitemcreated="gridView_ItemCreated" onitemdatabound="gridView_ItemDataBound">
            <clientsettings>
        <clientevents onrowselected="RowSelected" onrowdeselected="RowSelected" oncolumnclick="OnColumnClick" OnColumnSwapped="ColumnSwapped" OnGridCreated="OnGridCreated"/>
    </clientsettings>
        </telerik:RadGrid>

Columns are dynamic, created in code-behind to match configurable datasets, via gridView.Columns.Add.  Each column has UniqueName, SortExpression, and HeaderText properties set - first two to the field name, last to plain-English version of the field name with spaces, etc.  Data binding is via a data table created from search results:

 gridView.DataSource = allDocumentsTable;

and using the following JS to activate the header cell context menus:

 function ShowColumnHeaderMenu(ev, index) {
            var grid = $find("<%=gridView.ClientID %>");
            var columns = grid.get_masterTableView().get_columns();
            columns[index - 1].showHeaderMenu(ev, 5, 5);
        }

I'm able to group columns using the menu but the "ungroup" command in the menu does not work.  If I turn on the grouping panel as a test (we do not want this UI style in production code), I can ungroup columns using the panel, but that does not change the behavour of the ungroup command in the header menu; it still does not work.

I've tried this with the Q2 2014 release and the problem is reproducible in that version.

You have very useful property - EnableTimeIndependentFiltering for GridDateTimeColumn. But I need to use ItemTemplate and EditItemTemplate and this future missing in GridTemplateColumn. I try to use FilterTemplate with RadDatePicker, but then I have only "equal to" option for filtering. I don't want this. So my suggestion to you is to develop EnableTimeIndependentFiltering for the cases when user have to use GridTemplateColumn with DataType=System.DateTime.

We are using RadGrid in SharePoint Visual Webpart with FilterType="CheckList". What we need is to be able to filter the checklist further with auto filter textbox.
1. When the filter icon is clicked, it fills with all available options (say 100 + records).
2. User enters few characters (say first 4) in the textbox and the list gets filtered with the all options starting with... (resulting in 8 records)
3. User then selects the required option for the final filter.

Please find attached image for clarification.